Self-opening automatic work driving device



E. R. SMITH SSRN? SELF-OPENING AUTOMATIC WORK DRIVING DEVICE Filed March 26, 1957 2 Sheets-Shea?l l A7 Y 12 Y INVENTOR.

EDWIN R. SMITH.

Oct. 21, 1958 E. R. SMITH 293579167 SELF-OPENING AUTOMATIC WORK DRIVING DEVICE Filed March 26, 1957 2 Sheets-Sheet 2 mf' .UM

INVENTOR. EDWIN R. SMITH.

FQ- 5 BYM/A United States Patent O l 2,857,167 SELF-OPENING AUTQMATIC WORK DRIVING DEVICE Edwin R. Smith, Seneca Falls, N. Y., assigner to Seneca Falls Machine Company, Seneca Falls, N. Y., a corporation of Massachusetts Application March 26, 1957, Serial No. 648,583 1 Claim. (Cl. 279-106) This invention relates to a device for driving a piece of work which is rotatably mounted in a lathe or other machine tool. Such work is usually mounted on centers and the work driving jaws may be closed by centrifugal force.

In modern procedure, the work is commonly removed and replaced without stopping the rotation of the driving spindle. It is the general object of my present invention to provide improved means for counteracting centrifugal force when desired and for thus releasing a workpiece while the driving mechanism continues to rotate at substantial speed.

To the attainment of this object, I preferably provide means to positively engage and retract the centrifugally operated levers which close the driving jaws. I may also provide additional spring means for closing the jaws on the work when the driving device is not in rotation.

My invention further relates to arrangements and com-Y binations of parts which will be hereinafter described and more particularly pointed out in the appended claim.

A preferred form of the invention is shown in the accompanying drawings, in which Fig. l is an end View of my improved work-driving device but with cover plate removed;

Figs. 2 and 3 are longitudinal sections of the device, taken along the lines 2-2 and 3-3 in Fig. l respectively;

Fig. 4 is a detail transverse sectional view, taken along the line 4-4 of Fig. 3;

Figs. 5 and 6 are a plan view and side elevation of a lever-releasing member;

Figs. 7 and 8 are a plan view and side elevation of a driving jaw and an operating lever therefor; and

Fig. 9 is a plan View of a counter-weighted member to be described.

Referring to the drawings, I have shown my improved driving device as comprising a casing 10 secured to a disc 11 forming one end portion of the driving spindle 12. A cover plate 14 encloses the working parts of the driving device.

The workpiece as W (Fig. 2) is commonly mounted at one end on a live center 2t) which is slidable in a support 21 (Fig. 4) and which is engaged by a spring 22 which forces the center yieldingly outward within limits defined by a crosspin 23 and slots 24 in the member 21.

Driving jaws 30 are loosely mounted on pins 31 fixed in a slide 32 which is mounted to slide transversely between narrow limits in the casing or body member 10. The outer ends of the jaws 30 are segmentally curved at 30a to engage and fit similarly curved walls 33 in the slide 32, and these coacting curved surfaces form effective bearings for the jaws 30. The inner ends of the jaws have eccentrically curved faces 34 which engage and drive the work W in the usual Way.

Threaded studs 35 (Fig. 1) enter notches 36 in the slide 32 to limit its sliding displacement, and springseated flanged bushings 37 (Fig. l) engage shoulders 33 on the slide 32 and normally center the slide 32 in the casing 10.

Centrifugal levers 40 (Figs. 7 and 8) are also pivoted on the studs 31 and are provided with shoulders 41 and 42 which loosely engage the jaws 30 and cause them to follow the angular movement of the levers 40.

The outer end portions 40a of the levers are heavily weighted and tend to be forced outward by centrifugal force when the driving device is rotated. Such outward movement swings the jaws 30 against the work and affords firm driving contact.

As previously explained, it is commonly desirable to open the jaws 30 to release the work W while the driving spindle continues to rotate. Accordingly, I have provided each lever 40 with a side surface or shoulder 44 (Fig. 9) adapted to be engaged by a cam surface 45 (Fig. 5) at the outer end of a segmental sliding member 46 mounted on a collar 47 which is threaded to a release rod 48 (Fig. 2).

When the release rod 48 and collar 47 are moved to the right in Figs. 2 and 3, the cam surfaces 45 engage the shoulders 44 (Figs, 7 and 9) of the levers 40 and swing the lever-and-jaw assemblies clockwise to release the work.

The release rod 48 may be operated either manually or automatically when a workpiece is nished. It is thus possible to open the jaws and discharge the work by overcoming the centrifugal force while the driving spindle continues in rotation.

If it is desired to close the jaws against the work independently of centrifugal force as the cam member 46 is withdrawn, an auxiliary spring 50 (Fig. 7) may be mounted adjacent eac-h jaw 30 and these springs will swing the jaws to driving position as soon as the jaws are released by the cam member 46.

At relatively low speed operation, it may be unnecessary to use centrifugal force and the jaws may be closed solely by the springs 50 but the cam surfaces 45 on the end of the sliding member 46 will still be required to open the jaws. Under these conditions, the counterweight end portions 40a (Fig. 8) may be omitted or removed from the levers 40.

It will thus appear that I have provided relatively simple means by which the jaws 30 may be positively opened against centrifugal force or against the springs 50 whenever it is desired to release the work, and whether or not the driving spindle continues in rotation.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claim, but what I claim is:

A work-engaging and work-driving device comprising a rotatable body, a pair of jaws pivotally mounted on said body and having eccentric work-engaging inner end surfaces, counter-weighted members associated with said jaws and responsive to centrifugal force to close said jaws, each associated jaw and counter-weighted member having an engageable side surface, a pair of axially-disposed and slidable bars having end cam surfaces which directly engage said side surfaces and which are effective to mechanically open said jaws to release the Work, and an aXially-shiftable pull rod operable while the workdriving device continues to rotate and effective to move said axially-disposed bars and end cam surfaces axially in said Work-driving device to force said jaws to open against centrifugal force.

References Cited in the le of this patent UNITED STATES PATENTS 2,207,621 Hite July 9, 1940 2,225,377 Hussari Dec. 17, 1940 2,493,574 Durkee Jan. 3, 1950 2,672,780 Schurr Mar. 23, 1954 2,762,630 Coniglio Sept. 1l, 1956 2,784,977 Dinsmore Mar. 12, 1957 2,788,887 Johnson Apr. 16, 1957 

